In mobile communications, access to a mobile communication network is usually restricted to mobile communication devices being operated in connection with a valid subscription with a mobile network operator. Therefore, a mobile communication network identifies and authenticates mobile communication devices when they are accessing the network and authorize the devices to function in the network. For identifying and authenticating mobile communication devices, user identification modules are used that are included in the mobile communication devices used for accessing mobile communication networks. A user identification module stores data, which are used in the operation of the mobile communication device in a mobile communication system particularly including information and/or applications for identifying and/or authenticating a mobile communication device in a mobile communication network.
Usually, user identification modules are configured as so called smartcards, i.e. cards containing an embedded integrated circuit for storing and processing information. The cards are issued by or under the control of a network operator usually in response to a registration of a subscription. If the subscriber is an individual, the user identification module may be personal to the individual and used by the individual to activate a mobile communication device and use it for telecommunications purposes in a mobile communication system. In another example, a user identification module may be used in a telematics application to identify a particular telematics device for use in a mobile communication system. In each case, user identification modules are usually specific to a particular network (the so called home network) or its operator. In particular, identification and/or authentication information are determined by the home network operator and secret data stored in a user identification module are shared only with the home network operator.
In order to prevent unauthorized use and/or manipulation of sensitive data stored in a user identification module, those data are secured in a special way. For this purpose, the microcontroller of a smartcard comprising a user identification module usually provides a secure environment for the execution of applications and the storage of data. Moreover, the microcontroller is integrated into a secure hardware environment provided by the smartcard, which is physically protected against manipulations, such as, power analysis, reverse engineering, etc. Within such an environment sensitive data may be stored in the smartcard in such a way that the relevant data files cannot be modified after the sensitive information are stored therein once by the supplier of the user identification module at the time of manufacture.
Since usually the operator-related identification and authentication data are stored in a user identification module in a non-modifiable manner, it is not possible to reuse a user identification module after subscribing to another home network or the mobile communication network. In this case, the new home network operator has to issue a new user identification module comprising new identification and/or authentication data for use within the scope of the subscription to this operator. This is resource-consuming for the new mobile network operator that has to issue the card and for the user of a mobile communication device that has to change the user identification module in the mobile communication device. For the user, this has the further drawback that personal data stored in the user identification module during use thereof are lost.
A change of a user identification module is especially difficult in terms of the required logistics when telematics devices are involved which are incorporated into products. However, in some situations a change of the home network may be required or advantageous especially for those devices or products. For instance, a telematics device with its user identification module may be incorporated into a product when located in one country, but the product may then be exported or for other reasons relocated to another country for use therein. In this case, it would be advantageous to change the home network to one located in the new country. However, the destination may be unknown at the time when the device and its user identification module are incorporated into the product. In such a product, it would be advantageous to change the home network without having to change the user identification module in the product.